The majority of debt-related auto sales metrics have increased. Not only are 85% of new car purchases financed, but 53.8% of used car purchases also required financing – increases of 0.5% and 0.9% respectively over 2013 numbers. Used car debt is increasing at an even larger rate, with the average loan increasing to $18,258 (a 1.9% rise over 2013) and the average monthly car payment reaching $355 (a 1.1% increase over 2013).

Banks financed 35.6% of used car purchases amid a renewed focus on the used car market. The internal financing arms of the automakers are increasing their hold on the new car markets, covering over half of the second quarter’s new car loans.

While the overall percentage of those struggling to make car payments is relatively low, it is on the rise. Both 30 and 60-day delinquencies are up slightly over the previous year’s numbers, with the total value of 30-day delinquencies at $2.8 billion and 60-day delinquencies at $859 million.

All auto lender types are showing healthy growth in year-over-year loan volumes. Bank loans have increased by $31 billion, credit union loans have increased by $25 billion, finance company loans grew by $24 billion, and the captive finance arms of the automakers increased by $9 billion.

Overall, the short-term picture for the banks is positive with respect to auto loans. The top four banks in auto lending market share are Wells Fargo, Capital One, JPMorgan Chase, and Ally Financial (the former GMAC). Arguably, all four have had larger investor concerns than their performance in the auto loan market – but it would be worth monitoring their performance over the next three months to see if the delinquency levels begin to rise.

New car sales have been relatively strong, but there are warning signs on the horizon. A recent increase in the supply of used cars may drive prices down. Combined with a slowly growing economy and minimal wage growth, used cars are positioned to cut into new-car sales.

Meanwhile, some analysts are warning that an increasing amount of the U.S. auto sales is dependent on discounts and tolerance of subprime loans. According to Kelley Blue Book, incentives to buy have grown every month throughout 2014 and the estimated collective rebate and discount value in August 2014 is $2,800.

Chrysler in particular has been aggressive in the subprime market, according to Jessica Caldwell, a senior analyst at Edmunds.com. So far, the results have been impressive – 53 straight months of sales increases and a 19.9% increase in August sales over the previous year. However, increases in this behavior are going to perk up the ears of regulators, who have already started investigating Santander Consumer Holdings and GM’s financing group for securitized subprime loans.

According to the Experian report, the second quarter of 2014 showed a decline in subprime auto loans, so perhaps the subprime tendency has bottomed out. Even so, before you invest in a car company, it would not be a bad plan to investigate their loan holdings as well as the sales projections and company fundamentals.

In short, the vehicle finance market shows preliminary signs of behaviors that led to previous slumps, but the key word is preliminary. Invest in banks and the auto industry as it meets your investment needs – but keep an eye out for negative trends.